The Experts below are selected from a list of 34137 Experts worldwide ranked by ideXlab platform
Satoshi Nonami - One of the best experts on this subject based on the ideXlab platform.
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prediction of long term settlement and evaluation of Pore Water Pressure using particle filter
Soils and Foundations, 2019Co-Authors: Toshifumi Shibata, Takayuki Shuku, Akira Murakami, Shinichi Nishimura, Kazunori Fujisawa, Noritaka Hasegawa, Satoshi NonamiAbstract:Abstract The present paper showcases a numerical simulation of the long-term behavior of a foundation and an evaluation of the Pore Water Pressure on Kobe Airport Island. To calculate the behavior of the ground and the Pore Water Pressure, a numerical analysis is implemented using an elasto-plastic FEM for soil–Water coupled problems with the Cam-clay model. However, numerical difficulties still remain in estimating the elasto-plastic parameters because of the nonlinearity of the materials and the uncertainty of the initial/boundary conditions. To account for these difficulties, a data assimilation technique, the particle filter, is adopted to identify the soil parameters using field measurements. The numerical simulation is carried out with the identified parameters to predict the long-term settlement and to evaluate the Pore Water Pressure of the improved ground for two cases of boundary conditions. The outcomes show a good agreement with the direct measurements of the long-term settlement and the observed Pore Water Pressure.
Mladen Vucetic - One of the best experts on this subject based on the ideXlab platform.
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cyclic secant shear modulus and Pore Water Pressure change in sands at small cyclic strains
Journal of Geotechnical and Geoenvironmental Engineering, 2021Co-Authors: Mladen Vucetic, Harish Thangavel, Ahmadreza MortezaieAbstract:AbstractWhen fully saturated sandy soil is subjected to cyclic straining in undrained conditions, Pore Water Pressure increases and effective stress decreases. Therefore, it has been assumed that i...
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cyclic secant shear modulus versus Pore Water Pressure in sands at small cyclic strains
Soil Dynamics and Earthquake Engineering, 2015Co-Authors: Mladen Vucetic, Ahmadreza MortezaieAbstract:Abstract Cyclic strain-controlled behavior of fully saturated sands in undrained condition is analyzed at small cyclic shear strain amplitudes, γc, around the threshold shear strain for cyclic Pore Water Pressure buildup, γtp≈0.01%. The cyclic triaxial and simple shear test results obtained in the past by different researchers and the results of new cyclic simple shear tests reveal that: (i) at very small γc below γtp where there is no buildup of cyclic Pore Water Pressure, ΔuN, with the number of cycles, N, the cyclic secant shear modulus, GSN, initially increases with N for 10–20% of its initial value GS1 and then levels off or just slightly decreases, (ii) at small γc between γtp≈0.01% and 0.10–0.15%, ΔuN continuously increases with N while the modulus GSN first increases for up to 10% of GS1 and then gradually decreases, and (iii) at γc larger than approximately 0.15%, relatively large ΔuN develops with N while the modulus GSN constantly and significantly decreases. This means that at γc between γtp and 0.10–0.15% the sand stiffness initially increases with N in spite of the reduction of effective stresses caused by the cyclic Pore Water Pressures buildup. In this range of γc, the Pore Water Pressure ΔuN can reach up to 40% of the initial effective confining stress before GSN drops below GS1. The microstructural mechanisms believed to be responsible for such a complex behavior are discussed. It is suggested that during cyclic loading the changes at mineral-to-mineral junctions of grain contacts can cause soil stiffening while, at the same time, the buildup of cyclic Pore Water Pressure causes the softening.
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threshold shear strain for cyclic Pore Water Pressure in cohesive soils
Journal of Geotechnical and Geoenvironmental Engineering, 2006Co-Authors: Mladen VuceticAbstract:Threshold shear strain for cyclic Pore-Water Pressure, γt , is a fundamental property of fully saturated soils subjected to undrained cyclic loading. At cyclic shear strain amplitude, γc , larger than γt residual cyclic Pore-Water Pressure changes rapidly with the number of cycles, N , while at γc < γt such changes are negligible even at large N . To augment limited experimental data base of γt in cohesive soils, five values of γt for two elastic silts and a clay were determined in five special cyclic Norwegian Geotechnical Institute (NGI)-type direct simple shear (NGI-DSS), constant volume equivalent undrained tests. Threshold γt was also tested on one sand, with the results comparing favorably to published data. The test results confirm that γt in cohesive soils is larger than in cohesionless soils and that it generally increases with the soil’s plasticity index (PI). For the silts and clay having PI=14–30, γt =0.024–0.06% was obtained. Limited data suggest that γt in plastic silts and clays practically...
Shan Hongxian - One of the best experts on this subject based on the ideXlab platform.
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deep sea floor Pore Water Pressure long term observation automatic laying system and deep sea floor Pore Water Pressure long term observation automatic laying method
2015Co-Authors: Jia Yonggang, Zhang Shaotong, Wang Zhenhao, Guo Lei, Liu Xiaolei, Shan HongxianAbstract:The invention discloses a deep-sea floor Pore Water Pressure long-term observation automatic laying system and a deep-sea floor Pore Water Pressure long-term observation automatic laying method. The system comprises an automatic lifting Pore Pressure meter, a underWater acoustic/long wave communicator, a ship-borne controller and a laying apparatus; the automatic lifting Pore Pressure meter orderly comprises a lower drill, a balance weight, a master control cabin, a floating body material, an upper drill and a protective rest from bottom to top; the underWater acoustic/long wave communicator and the ship-borne controller are used for controlling the automatic lifting Pore Pressure meter. A laying bracket and the automatic lifting Pore Pressure are sent into the seabed surface through a hook while laying; the lower drill begins drilling hole to enter sediment, and the stops running after arriving a set depth; and then the hook is packed up through a cable to finish the laying. When the system is used for recycling, a releaser is started through the emission of a control signal, parts of the automatic lifting Pore Pressure meter except the lower drill and the balance weight thereof are separated so that the automatic lifting Pore Pressure meter is floated, and recycled. The repeated laying-recycling of a complex deep-sea instrument is avoided, the working efficiency is improved, the research cost is lowered, and the artificial disturbance on the field search environment in the laying-recycling process is avoided.
Toshifumi Shibata - One of the best experts on this subject based on the ideXlab platform.
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prediction of long term settlement and evaluation of Pore Water Pressure using particle filter
Soils and Foundations, 2019Co-Authors: Toshifumi Shibata, Takayuki Shuku, Akira Murakami, Shinichi Nishimura, Kazunori Fujisawa, Noritaka Hasegawa, Satoshi NonamiAbstract:Abstract The present paper showcases a numerical simulation of the long-term behavior of a foundation and an evaluation of the Pore Water Pressure on Kobe Airport Island. To calculate the behavior of the ground and the Pore Water Pressure, a numerical analysis is implemented using an elasto-plastic FEM for soil–Water coupled problems with the Cam-clay model. However, numerical difficulties still remain in estimating the elasto-plastic parameters because of the nonlinearity of the materials and the uncertainty of the initial/boundary conditions. To account for these difficulties, a data assimilation technique, the particle filter, is adopted to identify the soil parameters using field measurements. The numerical simulation is carried out with the identified parameters to predict the long-term settlement and to evaluate the Pore Water Pressure of the improved ground for two cases of boundary conditions. The outcomes show a good agreement with the direct measurements of the long-term settlement and the observed Pore Water Pressure.
Ahmadreza Mortezaie - One of the best experts on this subject based on the ideXlab platform.
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cyclic secant shear modulus and Pore Water Pressure change in sands at small cyclic strains
Journal of Geotechnical and Geoenvironmental Engineering, 2021Co-Authors: Mladen Vucetic, Harish Thangavel, Ahmadreza MortezaieAbstract:AbstractWhen fully saturated sandy soil is subjected to cyclic straining in undrained conditions, Pore Water Pressure increases and effective stress decreases. Therefore, it has been assumed that i...
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cyclic secant shear modulus versus Pore Water Pressure in sands at small cyclic strains
Soil Dynamics and Earthquake Engineering, 2015Co-Authors: Mladen Vucetic, Ahmadreza MortezaieAbstract:Abstract Cyclic strain-controlled behavior of fully saturated sands in undrained condition is analyzed at small cyclic shear strain amplitudes, γc, around the threshold shear strain for cyclic Pore Water Pressure buildup, γtp≈0.01%. The cyclic triaxial and simple shear test results obtained in the past by different researchers and the results of new cyclic simple shear tests reveal that: (i) at very small γc below γtp where there is no buildup of cyclic Pore Water Pressure, ΔuN, with the number of cycles, N, the cyclic secant shear modulus, GSN, initially increases with N for 10–20% of its initial value GS1 and then levels off or just slightly decreases, (ii) at small γc between γtp≈0.01% and 0.10–0.15%, ΔuN continuously increases with N while the modulus GSN first increases for up to 10% of GS1 and then gradually decreases, and (iii) at γc larger than approximately 0.15%, relatively large ΔuN develops with N while the modulus GSN constantly and significantly decreases. This means that at γc between γtp and 0.10–0.15% the sand stiffness initially increases with N in spite of the reduction of effective stresses caused by the cyclic Pore Water Pressures buildup. In this range of γc, the Pore Water Pressure ΔuN can reach up to 40% of the initial effective confining stress before GSN drops below GS1. The microstructural mechanisms believed to be responsible for such a complex behavior are discussed. It is suggested that during cyclic loading the changes at mineral-to-mineral junctions of grain contacts can cause soil stiffening while, at the same time, the buildup of cyclic Pore Water Pressure causes the softening.
